[dood]

Would someone be kind enough to explain simply what 3G and GPRS are and do? I'm a bit confused as I thought GPRS was about sending and receiving e-mails. I have been able to do this but now my service provider is advertising that GPRS is finally here!

Then with regards to internet, what is HDPSA?

[Obskure]

Hi. Gprs is a GSM term. Think of it as 2.5G(2G being basic GSM and WAP access). It is used to describe the speed that your phone can download from the "internet". Gprs, as such, has nothing to do with phone calls and and text messages. It is faster for wap access and email sending, retrieval etc.
3G is a term coined from "third generation". The first being anologue, second being GSM(digital). It allows download speeds of up to 384 kbps. Is advertised as being really useful for video calling and more realistic/faster web browsing.
Then, HSDPA(High Speed Download Packet Access) is what is though of as 3.5G. At the moment download speeds vary between networks. Here in Ireland, Vodafone offer 1.6Mbps, while 3 Irleland are touting 3.6 Mbps which will rise to 7.2 Mbps before the end of the year. HSDPA is useful for mobile data cards and modems for laptops etc because these wireless solutions offer faster than DSL broadband access to alot of people.
Hope that has been of some help to you, & if I have made a mistake Please feel free to set the record straight, everyone

[wombar]

Yep Obskure has the right of it. Here's a quick break down, it's not definitive and doesn't go into much detail, but should get you started.

GPRS = Dial Up Speed
3G = Broadband speed (kind of)
HSDPA = Faster than 3G